[CrOS Tether] Transform NetworkConnectionHandler to an interface.

chromeos/components/tether/initializer_unittest.cc

Index: chromeos/components/tether/initializer_unittest.cc
diff --git a/chromeos/components/tether/initializer_unittest.cc b/chromeos/components/tether/initializer_unittest.cc
index e0c276febddd0c58fa1c7bc97481951089810c09..8d9a6e693a8793c3d920e723ce91155376c7161a 100644
--- a/chromeos/components/tether/initializer_unittest.cc
+++ b/chromeos/components/tether/initializer_unittest.cc
@@ -89,6 +89,28 @@ class TestNetworkConnectionHandler : public NetworkConnectionHandler {
  public:
   TestNetworkConnectionHandler() : NetworkConnectionHandler() {}
   ~TestNetworkConnectionHandler() override {}
+
+  // NetworkConnectionHandler:
+  void ConnectToNetwork(const std::string& service_path,
+                        const base::Closure& success_callback,
+                        const network_handler::ErrorCallback& error_callback,
+                        bool check_error_state) override {}
+
+  void DisconnectNetwork(
+      const std::string& service_path,
+      const base::Closure& success_callback,
+      const network_handler::ErrorCallback& error_callback) override {}
+
+  bool HasConnectingNetwork(const std::string& service_path) override {
+    return false;
+  }
+
+  bool HasPendingConnectRequest() override { return false; }
+
+  void Init(NetworkStateHandler* network_state_handler,
+            NetworkConfigurationHandler* network_configuration_handler,
+            ManagedNetworkConfigurationHandler*
+                managed_network_configuration_handler) override {}
 };
 
 }  // namespace